I actually thought this book would be much better than it was. There is a coherent theoretical argument behind the whole import substitution, infant industries approach to development. I was hoping to see a more interesting/empirical defense of it (and maybe a more nuanced explanation of when/how it can work, and when it doesn't)...because development is ultimately an empirical question about "what works," not what makes sense in theory. Ha-Joon presents a basic version of theoretical argument, but then just does some historical story telling to explain why it is "correct." His argument is basically that all developed countries used protectionist trade policies...therefore, protectionist trade policies cause development.
But, there are also other common factors we could point to, i.e. many other potential variables behind growth/development (accumulation of capital, high savings rates, human capital, rule of law, functioning domestic markets, inclusive/exclusive institutions, exogenous technological developments, luck, etc.). I don't feel like he really addressed any other possible variables in why certain countries have developed rapidly. The economies that he pointed to also focused a lot on better economic policies in other areas, like education, etc. If you believe that another cause was really the key driver of growth in Asia (say rising human capital through education) then one could see development as something that happened unrelated to (or despite) protectionist trade policies (which just redistributed some gains/loses in an inefficient manner). The point being, his argument didn't seem to very effectively address how the policies he likes fit into a broader set of policies (education, health, relatively sound macroeconomic policies, etc.), and why the policies he likes were the decisive factor, and not other variables. Even if this is hard to prove definitively, he could have done a lot more to address it.
Ha-Joon also neglects to really discuss when, how, and why protectionist policies have failed. Many, many countries have tried similar policy recommendation unsuccessfully, but he barely even mentions that there have been failures. He presents his "story" as if only developed countries tried these policies, they worked, and then everyone tried to keep it a secret. Maybe I am wrong about this, but my perception is that import substitution/infant industrial policies have been tried in many places for a long time, and to mixed results. In this respect, he is vulnerable to the same criticism that he makes of his caricature of "neo-liberals," in that he offers panacea, but then doesn't explain why it has failed so often when tried in history. Real insight would have come from explaining when his recommendations do/don't work and why, a more nuanced view on how they should be implemented, etc.
Finally, in the later chapters he really fell into the habit of what seemed like attacking either dated views, or just straw men. His points were probably much stronger in 2008 when the book was published (or years earlier when he began working on it), but at least now a number of his claims about what "neo-liberals" (whoever these people might be) believe, or the IMF believes, seem untrue. Almost nobody mainstream supports 0% inflation targeting policies (my sense is most economist would consider that a very bad idea), deficit spending is not universally opposed (and the IMF regularly publishes "sustainability" analyses of debt/deficits, which would be a weird thing to do if you thought all deficits were unsustainable), etc. He also fails to mention in his tirade that the only time the IMF would even have any leverage on a country's domestic policies...is when that country is asking the IMF to give it money. Some of his points in later chapters are defensible ones that many people would agree with, but when he superficially or inaccurately present the opposing viewpoint (or maybe it is just really dated), it kind of gets at his credibility more than anything.